Planetary transmissions having two interconnecting members and at least two input clutches

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least eight forward speed ratios and one reverse speed ratio. The transmission family members include three planetary gear sets having seven torque-transmitting mechanisms, two interconnecting members, and a grounded planetary gear member. The powertrain includes an engine that is selectively connectable to at least one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The seven torque-transmitting mechanisms provide interconnections between various gear members, the input shaft and the transmission housing, and are operated in combinations of three to establish at least eight forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a family of power transmissions havingthree planetary gear sets that are controlled by seventorque-transmitting devices to provide at least eight forward speedratios and at least one reverse speed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times. The number of forward speed ratios that are availablein the transmission determines the number of times the engine torquerange is repeated. Early automatic transmissions had two speed ranges.This severely limited the overall speed range of the vehicle andtherefore required a relatively large engine that could produce a widespeed and torque range. This resulted in the engine operating at aspecific fuel consumption point during cruising, other than the mostefficient point. Therefore, manually-shifted (countershafttransmissions) were the most popular.

With the advent of three- and four-speed automatic transmissions, theautomatic shifting (planetary gear) transmission increased in popularitywith the motoring public. These transmissions improved the operatingperformance and fuel economy of the vehicle. The increased number ofspeed ratios reduces the step size between ratios and therefore improvesthe shift quality of the transmission by making the ratio interchangessubstantially imperceptible to the operator under normal vehicleacceleration.

It has been suggested that the number of forward speed ratios beincreased to six or more. Six-speed transmissions are disclosed in U.S.Pat. No. 4,070,927 issued to Polak on Jan. 31, 1978; and U.S. Pat. No.6,422,969 issued to Raghavan and Usoro on Jul. 23, 2002.

Six-speed transmissions offer several advantages over four- andfive-speed transmissions, including improved vehicle acceleration andimproved fuel economy. While many trucks employ power transmissionshaving six or more forward speed ratios, passenger cars are stillmanufactured with three- and four-speed automatic transmissions andrelatively few five or six-speed devices due to the size and complexityof these transmissions.

Seven-speed transmissions are disclosed in U.S. Pat. No. 6,623,397issued to Raghavan, Bucknor and Usoro. Eight speed transmissions aredisclosed in U.S. Pat. No. 6,425,841 issued to Haka. The Hakatransmission utilizes three planetary gear sets and six torquetransmitting devices, including two brakes and two clutches, to provideeight forward speed ratios and a reverse speed ratio. One of theplanetary gear sets is positioned and operated to establish two fixedspeed input members for the remaining two planetary gear sets. Seven-,eight- and nine-speed transmissions provide further improvements inacceleration and fuel economy over six-speed transmissions. However,like the six-speed transmissions discussed above, the development ofseven-, eight- and nine-speed transmissions has been precluded becauseof complexity, size and cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved familyof transmissions having three planetary gear sets controlled to provideat least eight forward speed ratios and at least one reverse speedratio.

In one aspect of the present invention, the family of transmissions hasthree planetary gear sets, each of which includes a first, second andthird member, which members may comprise a sun gear, a ring gear, or aplanet carrier assembly member, in any order.

In referring to the first, second and third gear sets in thisdescription and in the claims, these sets may be counted “first” to“third” in any order in the drawings (i.e., left to right, right toleft, etc.).

In another aspect of the present invention, the planetary gear sets maybe of the single pinion-type or of the double pinion-type.

In yet another aspect of the present invention, a first member of thefirst planetary gear set is continuously interconnected with a firstmember of the second planetary gear set through a first interconnectingmember.

In yet another aspect of the present invention, a second member of thesecond planetary gear set is continuously interconnected with a firstmember of the third planetary gear set through a second interconnectingmember.

In a further aspect of the present invention, a third member of thesecond planetary gear set is continuously connected with a stationarymember (transmission case).

In yet a further aspect of the invention, each family memberincorporates an output shaft which is continuously connected with atleast one member of the planetary gear sets, and an input shaft which isnot continuously connected with any member of the planetary gear setsbut is selectively connectable with at least one member of the planetarygear sets through at least one of seven torque-transmitting mechanisms.

In still a further aspect of the invention, a first torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst or third planetary gear set with the input shaft.

In another aspect of the invention, a second torque-transmittingmechanism, such as a clutch, selectively interconnects another member ofthe first or third planetary gear set with the input shaft.

In a still further aspect of the invention, a third torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst, second or third planetary gear set with the input shaft or withanother member of the first, second or third planetary gear set.

In a still further aspect of the invention, a fourth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst planetary gear set with a member of the second or third planetarygear set.

In a still further aspect of the invention, a fifth torque-transmittingmechanism, such as a clutch, selectively connects a member of the firstor third planetary gear set with another member of the first or thirdplanetary gear set. Alternatively, the fifth torque-transmittingmechanism, such as a brake, selectively connects a member of the firstor third planetary gear set with the stationary member (transmissioncase).

In still another aspect of the invention, a sixth torque-transmittingmechanism, such as a clutch, selectively connects a member of the firstor third planetary gear set with another member of the first, second orthird planetary gear set. Alternatively, the sixth torque-transmittingmechanism, such as a brake, selectively connects a member of the firstor third planetary gear set with the stationary member (transmissioncase).

In still another aspect of the invention, a seventh torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst, second or third planetary gear set with another member of thefirst, second or third planetary gear set. Alternatively, the seventhtorque-transmitting mechanism, such as a brake, selectively connects amember of the first, second or third planetary gear set with thestationary member (transmission case).

In still another aspect of the invention, the seven torque-transmittingmechanisms are selectively engageable in combinations of three to yieldat least eight forward speed ratios and at least one reverse speedratio.

The above objects and other objects, features, and advantages of thepresent invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

FIG. 1 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1 a;

FIG. 2 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 2 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2 a;

FIG. 3 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 3 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3 a;

FIG. 4 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 4 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4 a;

FIG. 5 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 5 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5 a;

FIG. 6 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 6 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6 a;

FIG. 7 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 7 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7 a;

FIG. 8 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 8 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8 a;

FIG. 9 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 9 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9 a;

FIG. 10 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 10 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 10 a;

FIG. 11 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 11 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 11 a;

FIG. 12 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 12 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 12 a;

FIG. 13 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 13 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 13 a;

FIG. 14 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 14 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 14 a;

FIG. 15 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

FIG. 15 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 15 a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, there is shown in FIG.1 a a powertrain 10 having a conventional engine 12, a planetarytransmission 14, and a conventional final drive mechanism 16.

The planetary transmission 14 includes an input shaft 17 connected withthe engine 12, a planetary gear arrangement 18, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 18 includes three planetary gear sets 20, 30 and 40.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly 26. The planet carrier assembly26 includes a plurality of pinion gears 27 rotatably mounted on acarrier member 29 and disposed in meshing relationship with both the sungear member 22 and the ring gear member 24.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 rotatablymounted on a carrier member 49 and disposed in meshing relationship withboth the sun gear member 42 and the ring gear member 44.

The planetary gear arrangement also includes seven torque-transmittingmechanisms 50, 52, 54, 56, 57, 58 and 59. The torque-transmittingmechanisms 50, 52, 54 and 56 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque-transmitting mechanisms57, 58 and 59 are stationary-type torque transmitting mechanisms,commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 24. The sun gear member 22 is continuously connected with thering gear member 34 through the interconnecting member 70. The planetcarrier assembly member 36 is continuously connected with the ring gearmember 44 through the interconnecting member 72. The sun gear member 32is continuously connected with the transmission housing 60.

The planet carrier assembly member 26 is selectively connectable withthe input shaft 17 through the clutch 50. The sun gear member 42 isselectively connectable with the input shaft 17 through the clutch 52.The ring gear member 34 is selectively connectable with the planetcarrier assembly member 46 through the clutch 54. The planet carrierassembly member 26 is selectively connectable with the planet carrierassembly member 46 through the clutch 56. The ring gear member 34 isselectively connectable with the transmission housing 60 through thebrake 57. The planet carrier assembly member 26 is selectivelyconnectable with the transmission housing 60 through the brake 58. Theplanet carrier assembly member 46 is selectively connectable with thetransmission housing through the brake 59.

As shown in FIG. 1 b, and in particular the truth table disclosedtherein, the torque-transmitting mechanisms are selectively engaged incombinations of three to provide eight forward speed ratios and onereverse speed ratio.

The reverse speed ratio is established with the engagement of theclutches 52, 54 and the brake 58. The clutch 52 connects the sun gearmember 42 with the input shaft 17. The clutch 54 connects the ring gearmember 34 with the planet carrier assembly member 46. The brake 58connects the planet carrier assembly member 26 with the transmissionhousing 60. The sun gear member 42 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 46 rotates at thesame speed as the ring gear member 34 and the sun gear member 22. Thering gear member 44 rotates at the same speed as the planet carrierassembly member 36. The speed of the planet carrier assembly member 46is determined from the speed of the ring gear member 44, the speed ofthe sun gear member 42, and the ring gear/sun gear tooth ratio of theplanetary gear set 40. The sun gear member 32 does not rotate. The speedof the planet carrier assembly member 36 is determined from the speed ofthe ring gear member 34 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The planet carrier assembly member 26 does notrotate. The ring gear member 24 rotates at the same speed as the outputshaft 19. The ring gear member 24, and therefore the output shaft 19,rotates at a speed determined from the speed of the sun gear member 22and the ring gear/sun gear tooth ratio of the planetary gear set 20. Thenumerical value of the reverse speed ratio is determined utilizing thering gear/sun gear tooth ratios of the planetary gear sets 20, 30 and40.

The first forward speed ratio is established with the engagement of theclutches 52, 56 and the brake 58. The clutch 52 connects the sun gearmember 42 with the input shaft 17. The clutch 56 connects the planetcarrier assembly member 26 with the planet carrier assembly member 46.The brake 48 connects the planet carrier assembly member 26 with thetransmission housing 60. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly members 26, 46do not rotate. The ring gear member 44 rotates at the same speed as theplanet carrier assembly member 36. The speed of the ring gear member 44is determined from the speed of the sun gear member 42 and the ringgear/sun gear tooth ratio of the planetary gear set 40. The sun gearmember 32 does not rotate. The ring gear member 34 rotates at the samespeed as the sun gear member 22. The speed of the planet carrierassembly member 36 is determined from the speed of the ring gear member34 and the ring gear/sun gear tooth ratio of the planetary gear set 30.The ring gear member 24 rotates at the same speed as the output shaft19. The ring gear member 24, and therefore the output shaft 19, rotatesat a speed determined from the speed of the sun gear member 22 and thering gear/sun gear tooth ratio of the planetary gear set 20. Thenumerical value of the first forward speed ratio is determined utilizingthe ratio of the ring gear/sun gear tooth ratios of the planetary gearsets 20, 30 and 40.

The second forward speed ratio is established with the engagement of theclutches 52, 56 and the brake 57. The clutch 52 connects the sun gearmember 42 with the input shaft 17. The clutch 56 connects the planetcarrier assembly member 26 with the planet carrier assembly member 46.The brake 57 connects the ring gear member 34 with the transmissionhousing 60. The sun gear member 42 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 46 rotates at thesame speed as the planet carrier assembly member 26. The ring gearmember 44, planetary gear set 30 and sun gear member 22 do not rotate.The planet carrier assembly member 46 rotates at a speed determined fromthe speed of the sun gear member 42 and the ring gear/sun gear toothratio of the planetary gear set 40. The ring gear member 24 rotates atthe same speed as the output shaft 19. The ring gear member 24, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the planet carrier assembly member 26 and the ring gear/sungear tooth ratio of the planetary gear set 20. The numerical value ofthe second forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 20 and 40.

The third forward speed ratio is established with the engagement of theclutches 52, 54 and 56. The clutch 52 connects the sun gear member 42with the input shaft 17. The clutch 54 connects the ring gear member 34with the planet carrier assembly member 46. The clutch 56 connects theplanet carrier assembly member 26 with the planet carrier assemblymember 46. The sun gear member 42 rotates at the same speed as the inputshaft 17. The planet carrier assembly member 46 rotates at the samespeed as the ring gear member 34, the planetary gear set 20, and theoutput shaft 19. The ring gear member 44 rotates at the same speed asthe planet carrier assembly member 36. The ring gear member 44 rotatesat a speed determined from the speed of the planet carrier assemblymember 46 and the ring gear/sun gear tooth ratio of the planetary gearset 40. The sun gear member 32 does not rotate. The speed of the ringgear member 34, and therefore the output shaft 19, is determined fromspeed of the planet carrier assembly member 36 and the ring gear/sungear tooth ratio of the planetary gear set 30. The numerical value ofthe third forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 30 and 40.

The fourth forward speed ratio is established with the engagement of theclutches 50, 52 and 56. The clutch 50 connects the planet carrierassembly member 26 with the input shaft 17. The clutch 52 connects thesun gear member 42 with the input shaft 17. The clutch 56 connects theplanet carrier assembly member 26 with the planet carrier assemblymember 46. The planetary gear set 40 and planet carrier assembly members26, 36 rotate at the same speed as the input shaft 17. The sun gearmember 32 does not rotate. The ring gear member 34 rotates at the samespeed as the sun gear member 22. The ring gear member 34 rotates at aspeed determined from the speed of the planet carrier assembly member 36and the ring gear/sun gear tooth ratio of the planetary gear set 30. Thering gear member 24 rotates at the same speed as the output shaft 19.The ring gear member 24, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member26, the speed of the sun gear member 22, and the ring gear/sun geartooth ratio of the planetary gear set 20. The numerical value of thefourth forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 20 and 30.

The fifth forward speed ratio is established with the engagement of theclutches 50, 54 and 56. In this configuration, the input shaft 17 isdirectly connected to the output shaft 19.

The sixth forward speed ratio is established with the engagement of theclutches 50, 52 and 54. The clutch 50 connects the planet carrierassembly member 26 with the input shaft 17. The clutch 52 connects thesun gear member 42 with the input shaft 17. The clutch 54 connects thering gear member 34 with the planet carrier assembly member 46. The sungear member 42 rotates at the same speed as the input shaft 17. Theplanet carrier assembly member 46 rotates at the same speed as the ringgear member 34 and the sun gear member 22. The ring gear member 44rotates at the same speed as the planet carrier assembly member 36. Thespeed of the planet carrier assembly member 46 is determined from thespeed of the ring gear member 44, the speed of the sun gear member 42and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thesun gear member 32 does not rotate. The speed of the planet carrierassembly member 36 is determined from the speed of the ring gear member34 and the ring gear/sun gear tooth ratio of the planetary gear set 30.The planet carrier assembly member 26 rotates at the same speed as theinput shaft 17. The ring gear member 24 rotates at the same speed as theoutput shaft 19. The ring gear member 24, and therefore the output shaft19, rotates at a speed determined from the speed of the planet carrierassembly member 26, the speed of the sun gear member 22, and the ringgear/sun gear tooth ratio of the planetary gear set 20. The numericalvalue of the sixth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20, 30 and 40.

The seventh forward speed ratio is established with the engagement ofthe clutches 50, 52 and the brake 57. The clutch 50 connects the planetcarrier assembly member 26 with the input shaft 17. The clutch 52connects the sun gear member 42 with the input shaft 17. The brake 57connects the ring gear member 34 with the transmission housing 60. Thesun gear member 42 rotates at the same speed as the input shaft 17. Thering gear member 44, planetary gear set 30, and sun gear member 22 donot rotate. The planet carrier assembly member 26 rotates at the samespeed as the input shaft 17. The ring gear member 24 rotates at the samespeed as the output shaft 19. The ring gear member 24, and therefore theoutput shaft 19, rotates at a speed determined from the speed of theplanet carrier assembly member 26 and the ring gear/sun gear tooth ratioof the planetary gear set 20. The numerical value of the seventh forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 20.

The eighth forward speed ratio is established with the engagement of theclutches 50, 52 and the brake 59. The clutch 50 connects the planetcarrier assembly member 26 with the input shaft 17. The clutch 52connects the sun gear member 42 with the input shaft 17. The brake 59connects the planet carrier assembly member 46 with the transmissionhousing 60. The sun gear member 42 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 46 does not rotate.The ring gear member 44 rotates at the same speed as the planet carrierassembly member 36. The speed of the ring gear member 44 is determinedfrom the speed of the sun gear member 42 and the ring gear/sun geartooth ratio of the planetary gear set 40. The sun gear member 32 doesnot rotate. The ring gear member 34 rotates at the same speed as the sungear member 22. The speed of the planet carrier assembly member 36 isdetermined from the speed of the ring gear member 34 and the ringgear/sun gear tooth ratio of the planetary gear set 30. The planetcarrier assembly member 26 rotates at the same speed as the input shaft17. The ring gear member 24 rotates at the same speed as the outputshaft 19. The ring gear member 24, and therefore the output shaft 19,rotates at a speed determined from the speed of the planet carrierassembly member 26, the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The numericalvalue of the eighth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20, 30 and 40.

As set forth above, the engagement schedule for the torque-transmittingmechanisms is shown in the truth table of FIG. 1 b. This truth tablealso provides an example of speed ratios that are available utilizingthe ring gear/sun gear tooth ratios given by way of example in FIG. 1 b.The N_(R1)/N_(S1) value is the tooth ratio of the planetary gear set 20;the N_(R2)/N_(S2) value is the tooth ratio of the planetary gear set 30;and the N_(R3)/N_(S3) value is the tooth ratio of the planetary gear set40. Also, the chart of FIG. 1 b describes the ratio steps that areattained utilizing the sample of tooth ratios given. For example, thestep ratio between the first and second forward speed ratios is 1.80,while the step ratio between the reverse and first forward ratio is−0.94.

FIG. 2 a shows a powertrain 110 having a conventional engine 12, aplanetary transmission 114, and a conventional final drive mechanism 16.

The planetary transmission 114 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 118, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 118 includes three planetary gearsets 120, 130 and 140.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly 126. The planet carrierassembly 126 includes a plurality of pinion gears 127 rotatably mountedon a carrier member 129 and disposed in meshing relationship with boththe sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of pinion gears 137 rotatablymounted on a carrier member 139 and disposed in meshing relationshipwith both the sun gear member 132 and the ring gear member 134.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 rotatablymounted on a carrier member 149 and disposed in meshing relationshipwith both the sun gear member 142 and the ring gear member 144.

The planetary gear arrangement 118 also includes seventorque-transmitting mechanisms 150, 152, 154, 156, 157, 158 and 159. Thetorque-transmitting mechanisms 150, 152, 154, 156 and 157 arerotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 158 and 159 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 146. The ring gear member 124 is continuouslyconnected with the planet carrier assembly member 136 through theinterconnecting member 170. The ring gear member 134 is continuouslyconnected with the ring gear member 134 through the interconnectingmember 172. The sun gear member 132 is continuously connected with thetransmission housing 160.

The planet carrier assembly member 126 is selectively connectable withthe input shaft 17 through the clutch 150. The sun gear member 142 isselectively connectable with the input shaft 17 through the clutch 152.The planet carrier assembly member 126 is selectively connectable withthe ring gear member 134 through the clutch 154. The sun gear member 122is selectively connectable with the sun gear member 142 through theclutch 156. The sun gear member 122 is selectively connectable with theplanet carrier assembly member 146 through the clutch 157. The ring gearmember 124 is selectively connectable with the transmission housing 160through the brake 158. The planet carrier assembly member 126 isselectively connectable with the transmission housing 160 through thebrake 159.

The truth table of FIG. 2 b describes the engagement sequence utilizedto provide nine forward speed ratios and one reverse speed ratio in theplanetary gear arrangement 118 shown in FIG. 2 a, as well as extrafifth, seventh and eighth forward speed ratios.

The truth tables given in FIGS. 2 b, 3 b, 4 b, 5 b, 6 b, 7 b, 8 b, 9 b,10 b, 11 b, 12 b, 13 b, 14 b and 15 b show the engagement sequences forthe torque-transmitting mechanisms to provide at least eight forwardspeed ratios and at least one reverse ratio. As shown and describedabove for the configuration in FIG. 1 a, those skilled in the art willunderstand from the respective truth tables how the speed ratios areestablished through the planetary gear sets identified in the writtendescription.

As set forth above, the truth table of FIG. 2 b describes the engagementsequence of the torque-transmitting mechanisms utilized to provide thereverse drive ratio and nine forward speed ratios, as well as the extrafifth, seventh and eighth forward speed ratios. The truth table alsoprovides an example of the ratios that can be attained with the familymembers shown in FIG. 2 a utilizing the sample tooth ratios given inFIG. 2 b. The N_(R1)/N_(S1) value is the tooth ratio of the planetarygear set 120; the N_(R2)/N_(S2) value is the tooth ratio of theplanetary gear set 130; and the N_(R3)/N_(S3) value is the tooth ratioof the planetary gear set 140. Also shown in FIG. 2 b are the ratiosteps between single step ratios in the forward direction as well as thereverse to first step ratio. For example, the first to second step ratiois 1.52.

Turning to FIG. 3 a, a powertrain 210 includes the engine 12, aplanetary transmission 214, and a final drive mechanism 16. Theplanetary transmission 214 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 218, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 218 includes three planetary gearsets 220, 230 and 240.

The planetary gear set 220 includes a sun gear member 222, a ring gearmember 224, and a planet carrier assembly 226. The planet carrierassembly 226 includes a plurality of pinion gears 227 rotatably mountedon a carrier member 229 and disposed in meshing relationship with boththe sun gear member 222 and the ring gear member 224.

The planetary gear set 230 includes a sun gear member 232, a ring gearmember 234, and a planet carrier assembly member 236. The planet carrierassembly member 236 includes a plurality of pinion gears 237 rotatablymounted on a carrier member 239 and disposed in meshing relationshipwith both the sun gear member 232 and the ring gear member 234.

The planetary gear set 240 includes a sun gear member 242, a ring gearmember 244, and a planet carrier assembly member 246. The planet carrierassembly member 246 includes a plurality of pinion gears 247 rotatablymounted on a carrier member 249 and disposed in meshing relationshipwith both the sun gear member 242 and the ring gear member 244.

The planetary gear arrangement 218 also includes seventorque-transmitting mechanisms 250, 252, 254, 256, 257, 258 and 259. Thetorque-transmitting mechanisms 250, 252, 254, 256, 257 and 258 arerotating type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanism 259 is a stationary-type torquetransmitting mechanism, commonly termed brake or reaction clutch.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 244. The planet carrier assembly member 226 is continuouslyconnected with the planet carrier assembly member 236 through theinterconnecting member 270. The ring gear member 234 is continuouslyconnected with the planet carrier assembly member 246 through theinterconnecting member 272. The sun gear member 232 is continuouslyconnected with the transmission housing 260.

The ring gear member 224 is selectively connectable with the input shaft17 through the clutch 250. The planet carrier assembly member 246 isselectively connectable with the input shaft 17 through the clutch 252.The sun gear member 242 is selectively connectable with the input shaft17 through the clutch 254. The planet carrier assembly member 236 isselectively connectable with the ring gear member 244 through the clutch256. The ring gear member 234 is selectively connectable with the sungear member 222 through the clutch 257. The sun gear member 222 isselectively connectable with the sun gear member 242 through the clutch258. The ring gear member 224 is selectively connectable with thetransmission housing through the brake 259.

As shown in the truth table in FIG. 3 b, the torque-transmittingmechanisms are engaged in combinations of three to establish eightforward speed ratios and one reverse speed ratio, as well as extrasecond, fifth and eighth forward speed ratios.

As previously set forth, the truth table of FIG. 3 b describes thecombinations of engagements utilized for the forward and reverse speedratios. The truth table also provides an example of speed ratios thatare available with the family member described above. These examples ofspeed ratios are determined utilizing the tooth ratios given in FIG. 3b. The N_(R1)/N_(S1) value is the tooth ratio of the planetary gear set220; the N_(R2)/N_(S2) value is the tooth ratio of the planetary gearset 230; and the N_(R3)/N_(S3) value is the tooth ratio of the planetarygear set 240. Also depicted in FIG. 3 b is a chart representing theratio steps between adjacent forward speed ratios and between the firstand reverse speed ratio. For example, the first to second ratiointerchange has a step of 1.55.

A powertrain 310, shown in FIG. 4 a, includes the engine 12, a planetarytransmission 314, and the final drive mechanism 16. The planetarytransmission 314 includes an input shaft 17 continuously connected withthe engine 12, a planetary gear arrangement 318, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 318 includes three planetary gear sets 320, 330 and340.

The planetary gear set 320 includes a sun gear member 322, a ring gearmember 324, and a planet carrier assembly member 326. The planet carrierassembly member 326 includes a plurality of pinion gears 327 rotatablymounted on a carrier member 329 and disposed in meshing relationshipwith both the sun gear member 322 and the ring gear member 324.

The planetary gear set 330 includes a sun gear member 332, a ring gearmember 334, and a planet carrier assembly member 336. The planet carrierassembly member 336 includes a plurality of pinion gears 337 rotatablymounted on a carrier member 339 and disposed in meshing relationshipwith both the sun gear member 332 and the ring gear member 334.

The planetary gear set 340 includes a sun gear member 342, a ring gearmember 344, and a planet carrier assembly member 346. The planet carrierassembly member 346 includes a plurality of pinion gears 347 rotatablymounted on a carrier member 349 and disposed in meshing relationshipwith both the sun gear member 342 and the ring gear member 344.

The planetary gear arrangement 318 also includes seventorque-transmitting mechanisms 350, 352, 354, 356, 357, 358 and 359. Thetorque-transmitting mechanisms 350, 352, 354, 356, 357, 358 and 359 areall rotating type torque-transmitting mechanisms, commonly termedclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 324. The sun gear member 322 is continuously connected with thesun gear member 332 through the interconnecting member 370. The planetcarrier assembly member 336 is continuously connected with the sun gearmember 342 through the interconnecting member 372. The ring gear member334 is continuously connected with the transmission housing 360.

The planet carrier assembly member 326 is selectively connectable withthe input shaft 17 through the clutch 350. The planet carrier assemblymember 346 is selectively connectable with the input shaft 17 throughthe clutch 352. The ring gear member 344 is selectively connectable withthe input shaft 17 through the clutch 354. The ring gear member 324 isselectively connectable with the planet carrier assembly member 326through the clutch 356. The sun gear member 332 is selectivelyconnectable with the planet carrier assembly member 346 through theclutch 357. The sun gear member 332 is selectively connectable with thering gear member 344 through the clutch 358. The ring gear member 324 isselectively connectable with the planet carrier assembly member 336through the clutch 359.

The truth table shown in FIG. 4 b describes the engagement combinationand the engagement sequence necessary to provide the reverse drive ratioand eight forward speed ratios, as well as extra fourth and eighthforward speed ratios. A sample of the numerical values for the ratios isalso provided in the truth table of FIG. 4 b. These values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 4 b. The N_(R1)/N_(S1) value is the tooth ratio for the planetarygear set 320; the N_(R2)/N_(S2) value is the tooth ratio for theplanetary gear set 330; and the N_(R3)/N_(S3) value is the tooth ratiofor the planetary gear set 340. Also given in FIG. 4 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reverse to first forward speed ratio. For example, the first tosecond forward speed ratio step is 1.48.

A powertrain 410, shown in FIG. 5 a, includes the engine 12, a planetarytransmission 414 and the final drive mechanism 16. The planetarytransmission 414 includes a planetary gear arrangement 418, input shaft17 and output shaft 19. The planetary gear arrangement 418 includesthree simple planetary gear sets 420, 430 and 440.

The planetary gear set 420 includes a sun gear member 422, a ring gearmember 424, and a planet carrier assembly 426. The planet carrierassembly 426 includes a plurality of pinion gears 427 rotatably mountedon a carrier member 429 and disposed in meshing relationship with boththe sun gear member 422 and the ring gear member 424.

The planetary gear set 430 includes a sun gear member 432, a ring gearmember 434, and a planet carrier assembly member 436. The planet carrierassembly member 436 includes a plurality of pinion gears 437 rotatablymounted on a carrier member 439 and disposed in meshing relationshipwith both the ring gear member 434 and the sun gear member 432.

The planetary gear set 440 includes a sun gear member 442, a ring gearmember 444, and a planet carrier assembly member 446. The planet carrierassembly member 446 includes a plurality of pinion gears 447 rotatablymounted on a carrier member 449 and disposed in meshing relationshipwith both the sun gear member 442 and the ring gear member 444.

The planetary gear arrangement 418 also includes seventorque-transmitting mechanisms 450, 452, 454, 456, 457, 458 and 459. Thetorque-transmitting mechanisms 450, 452, 454 and 456 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 457, 458 and 459 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 426. The ring gear member 424 is continuouslyconnected with the planet carrier assembly member 436 through theinterconnecting member 470. The ring gear member 434 is continuouslyconnected with the ring gear member 444 through the interconnectingmember 472. The sun gear member 432 is continuously connected with thetransmission housing 460.

The sun gear member 422 is selectively connectable with the input shaft17 through the clutch 450. The sun gear member 442 is selectivelyconnectable with the input shaft 17 through the clutch 452. The planetcarrier assembly member 426 is selectively connectable with the planetcarrier assembly member 446 through the clutch 454. The sun gear member422 is selectively connectable with the planet carrier assembly member446 through the clutch 456. The ring gear member 444 is selectivelyconnectable with the transmission housing 460 through the brake 457. Thesun gear member 442 is selectively connectable with the transmissionhousing through the brake 458. The planet carrier assembly member 446 isselectively connectable with the transmission housing 460 through thebrake 459.

The truth table shown in FIG. 5 b describes the engagement combinationand sequence of the torque-transmitting mechanisms 450, 452, 454, 456,457, 458 and 459 that are employed to provide the forward and reversedrive ratios.

Also given in the truth table of FIG. 5 b is a set of numerical valuesthat are attainable with the present invention utilizing the ringgear/sun gear tooth ratios shown. The N_(R1)/N_(S1) value is the toothratio of the planetary gear set 420; the N_(R2)/N_(S2) value is thetooth ratio of the planetary gear set 430; and the N_(R3)/N_(S3) valueis the tooth ratio of the planetary gear set 440.

FIG. 5 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is2.50.

A powertrain 510, shown in FIG. 6 a, includes an engine 12, a planetarygear transmission 514 and the final drive mechanism 16. The planetarytransmission 514 includes the input shaft 17, a planetary geararrangement 518 and the output shaft 19. The planetary gear arrangement518 includes three planetary gear sets 520, 530 and 540.

The planetary gear set 520 includes a sun gear member 522, a ring gearmember 524, and a planet carrier assembly 526. The planet carrierassembly 526 includes a plurality of pinion gears 527 rotatably mountedon a carrier member 529 and disposed in meshing relationship with boththe sun gear member 522 and the ring gear member 524.

The planetary gear set 530 includes a sun gear member 532, a ring gearmember 534, and a planet carrier assembly member 536. The planet carrierassembly member 536 includes a plurality of pinion gears 537 rotatablymounted on a carrier member 539 and disposed in meshing relationshipwith both the sun gear member 532 and the ring gear member 534.

The planetary gear set 540 includes a sun gear member 542, a ring gearmember 544, and a planet carrier assembly member 546. The planet carrierassembly member 546 includes a plurality of pinion gears 547 rotatablymounted on a carrier member 549 and disposed in meshing relationshipwith both the sun gear member 542 and the ring gear member 544.

The planetary gear arrangement 518 also includes seventorque-transmitting mechanisms 550, 552, 554, 556, 557, 558 and 559. Thetorque-transmitting mechanisms 550, 552, 554, 556 and 557 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 558 and 559 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 544. The planet carrier assembly member 526 is continuouslyconnected with the ring gear member 534 through the interconnectingmember 570. The planet carrier assembly member 536 is continuouslyconnected with the sun gear member 542 through the interconnectingmember 572. The sun gear member 532 is continuously connected with thetransmission housing 560.

The ring gear member 524 is selectively connectable with the input shaft17 through the clutch 550. The sun gear member 522 is selectivelyconnectable with the input shaft 17 through the clutch 552. The planetcarrier assembly member 546 is selectively connectable with the inputshaft 17 through the clutch 554. The ring gear member 524 is selectivelyconnectable with the planet carrier assembly member 536 through theclutch 556. The planet carrier assembly member 546 is selectivelyconnectable with the sun gear member 542 through the clutch 557. Thering gear member 524 is selectively connectable with the transmissionhousing 560 through the brake 558. The planet carrier assembly member546 is selectively connectable with the transmission housing 560 throughthe brake 559.

The truth table shown in FIG. 6 b describes the engagement sequence andcombination of the torque-transmitting mechanisms to provide fourreverse speed ratios and eight forward speed ratios. The chart of FIG. 6b describes the ratio steps between adjacent forward speed ratios andthe ratio step between the reverse and first forward speed ratio.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6 b. TheN_(R1)/N_(S1) value is the tooth ratio of the planetary gear set 520;the N_(R2)/N_(S2) value is the tooth ratio of the planetary gear set530; and the N_(R3)/N_(S3) value is the tooth ratio of the planetarygear set 540.

A powertrain 610, shown in FIG. 7 a, has the engine 12, a planetarytransmission 614 and the final drive mechanism 16. The planetarytransmission 614 includes the input shaft 17, a planetary geararrangement 618 and the output shaft 19. The planetary gear arrangement618 includes three planetary gear sets 620, 630 and 640.

The planetary gear set 620 includes a sun gear member 622, a ring gearmember 624, and a planet carrier assembly 626. The planet carrierassembly 626 includes a plurality of pinion gears 627 rotatably mountedon a carrier member 629 and disposed in meshing relationship with boththe sun gear member 622 and the ring gear member 624.

The planetary gear set 630 includes a sun gear member 632, a ring gearmember 634, and a planet carrier assembly member 636. The planet carrierassembly member 636 includes a plurality of pinion gears 637 rotatablymounted on a carrier member 639 and disposed in meshing relationshipwith both the sun gear member 632 and the ring gear member 634.

The planetary gear set 640 includes a sun gear member 642, a ring gearmember 644, and a planet carrier assembly member 646. The planet carrierassembly member 646 includes a plurality of pinion gears 647 rotatablymounted on a carrier member 649 and disposed in meshing relationshipwith both the sun gear member 642 and the ring gear member 644.

The planetary gear arrangement 618 also includes seventorque-transmitting mechanisms 650, 652, 654, 656, 657, 658 and 659. Thetorque-transmitting mechanisms 650, 652, 654, 656 and 657 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 658 and 659 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 646. The ring gear member 624 is continuouslyconnected with the planet carrier assembly member 636 through theinterconnecting member 670. The sun gear member 632 is continuouslyconnected with the sun gear member 642 through the interconnectingmember 672. The ring gear member 634 is continuously connected with thetransmission housing 660.

The planet carrier assembly member 626 is selectively connectable withthe input shaft 17 through the clutch 650. The ring gear member 644 isselectively connectable with the input shaft 17 through the clutch 652.The planet carrier assembly member 626 is selectively connectable withthe planet carrier assembly member 646 through the clutch 654. The sungear member 622 is selectively connectable with the planet carrierassembly member 646 through the clutch 656. The sun gear member 622 isselectively connectable with the ring gear member 644 through the clutch657. The ring gear member 624 is selectively connectable with thetransmission housing 660 through the brake 658. The planet carrierassembly member 626 is selectively connectable with the transmissionhousing 660 through the brake 659.

The truth table shown in FIG. 7 b describes the combination oftorque-transmitting mechanism engagements that will provide the reversedrive ratio and nine forward speed ratios, as well as the sequence ofthese engagements and interchanges.

The ratio values given are by way of example and are establishedutilizing the ring gear/sun gear tooth ratios given in FIG. 7 b. Forexample, the N_(R1)/N_(S1) value is the tooth ratio of the planetarygear set 620; the N_(R2)/N_(S2) value is the tooth ratio of theplanetary gear set 630; and the N_(R3)/N_(S3) value is the tooth ratioof the planetary gear set 640. The ratio steps between adjacent forwardratios and the reverse to first ratio are also given in FIG. 7 b.

A powertrain 710, shown in FIG. 8 a, has the conventional engine 12, aplanetary transmission 714, and the conventional final drive mechanism16. The engine 12 is drivingly connected with the planetary transmission714 through the input shaft 17. The planetary transmission 714 isdrivingly connected with the final drive mechanism 16 through the outputshaft 19. The planetary transmission 714 includes a planetary geararrangement 718 that has a first planetary gear set 720, a secondplanetary gear set 730, and a third planetary gear set 740.

The planetary gear set 720 includes a sun gear member 722, a ring gearmember 724, and a planet carrier assembly 726. The planet carrierassembly 726 includes a plurality of pinion gears 727 rotatably mountedon a carrier member 729. The pinion gears 727 are disposed in meshingrelationship with the sun gear member 722 and the ring gear member 724.

The planetary gear set 730 includes a sun gear member 732, a ring gearmember 734, and a planet carrier assembly member 736. The planet carrierassembly member 736 includes a plurality of pinion gears 737 rotatablymounted on a carrier member 739 and disposed in meshing relationshipwith both the sun gear member 732 and the ring gear member 734.

The planetary gear set 740 includes a sun gear member 742, a ring gearmember 744, and a planet carrier assembly member 746. The planet carrierassembly member 746 includes a plurality of pinion gears 747 rotatablymounted on a carrier member 749 and disposed in meshing relationshipwith both the sun gear member 742 and the ring gear member 744.

The planetary gear arrangement 718 also includes seventorque-transmitting mechanisms 750, 752, 754, 756, 757, 758 and 759. Thetorque-transmitting mechanisms 750, 752, 754, 756 and 757 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 758 and 759 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the sun gearmember 722. The ring gear member 724 is continuously connected with theplanet carrier assembly member 736 through the interconnecting member770. The ring gear member 734 is continuously connected with the planetcarrier assembly member 746 through the interconnecting member 772. Thesun gear member 732 is continuously connected with the transmissionhousing 760.

The planet carrier assembly member 726 is selectively connectable withthe input shaft 17 through the clutch 750. The planet carrier assemblymember 746 is selectively connectable with the input shaft 17 throughthe clutch 752. The sun gear member 742 is selectively connectable withthe input shaft 17 through the clutch 754. The ring gear member 724 isselectively connectable with the planet carrier assembly member 726through the clutch 756. The planet carrier assembly member 736 isselectively connectable with the ring gear member 744 through the clutch757. The planet carrier assembly member 726 is selectively connectablewith the transmission housing 760 through the brake 758. The ring gearmember 744 is selectively connectable with the transmission housing 760through the brake 759.

The truth table of FIG. 8 b defines the torque-transmitting mechanismengagement sequence utilized for each of the forward and reverse speedratios. Also given in the truth table is a set of numerical values thatare attainable with the present invention utilizing the ring gear/sungear tooth ratios given in FIG. 8 b. The N_(R1)/N_(S1) value is thetooth ratio of the planetary gear set 720; the N_(R2)/N_(S2) value isthe tooth ratio of the planetary gear set 730; and the N_(R3)/N_(S3)value is the tooth ratio of the planetary gear set 740.

FIG. 8 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.93.

A powertrain 810, shown in FIG. 9 a, has the conventional engine 12, aplanetary transmission 814, and the final drive mechanism 16. The engine12 is drivingly connected with the planetary transmission 814 throughthe input shaft 17. The planetary transmission 814 is drivinglyconnected with the final drive mechanism 16 through the output shaft 19.The planetary transmission 814 includes a planetary gear arrangement 818that has a first planetary gear set 820, a second planetary gear set830, and a third planetary gear set 840.

The planetary gear set 820 includes a sun gear member 822, a ring gearmember 824, and a planet carrier assembly 826. The planet carrierassembly 826 includes a plurality of pinion gears 827 rotatably mountedon a carrier member 829 and disposed in meshing relationship with thesun gear member 822 and the ring gear member 824.

The planetary gear set 830 includes a sun gear member 832, a ring gearmember 834, and a planet carrier assembly member 836. The planet carrierassembly member 836 includes a plurality of pinion gears 837 rotatablymounted on a carrier member 839 and disposed in meshing relationshipwith both the sun gear member 832 and the ring gear member 834.

The planetary gear set 840 includes a sun gear member 842, a ring gearmember 844, and a planet carrier assembly member 846. The planet carrierassembly member 846 includes a plurality of pinion gears 847 rotatablymounted on a carrier member 849 and disposed in meshing relationshipwith both the ring gear member 844 and the sun gear member 842.

The planetary gear arrangement 818 also includes seventorque-transmitting mechanisms 850, 852, 854, 856, 857, 858 and 859. Thetorque-transmitting mechanisms 850, 852, 854, 856 and 857 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 858 and 859 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 826. The ring gear member 824 is continuouslyconnected with the ring gear member 834 through the interconnectingmember 870. The planet carrier assembly member 836 is continuouslyconnected with the planet carrier assembly member 846 through theinterconnecting member 872. The sun gear member 832 is continuouslyconnected with the transmission housing 860.

The sun gear member 822 is selectively connectable with the input shaft17 through the clutch 850. The ring gear member 844 is selectivelyconnectable with the input shaft 17 through the clutch 852. The planetcarrier assembly member 846 is selectively connectable with the inputshaft 17 through the clutch 854. The planet carrier assembly member 826is selectively connectable with the sun gear member 842 through theclutch 856. The sun gear member 822 is selectively connectable with thesun gear member 842 through the clutch 857. The planet carrier assemblymember 846 is selectively connectable with the transmission housing 860through the brake 858. The ring gear member 844 is selectivelyconnectable with the transmission housing 860 through the brake 859.

The truth table shown in FIG. 9 b defines the torque-transmittingmechanism engagement sequence that provides two reverse speed ratios andeight forward speed ratios shown in the truth table and available withthe planetary gear arrangement 818, as well as extra seventh and eighthforward speed ratios. A sample of numerical values for the individualratios is also given in the truth table of FIG. 9 b. These numericalvalues have been calculated using the ring gear/sun gear tooth ratiosalso given by way of example in FIG. 9 b. The N_(R1)/N_(S1) value is thetooth ratio of the planetary gear set 820; the N_(R2)/N_(S2) value isthe tooth ratio of the planetary gear set 830; and the N_(R3)/N_(S3)value is the tooth ratio of the planetary gear set 840. FIG. 9 b alsodescribes the ratio steps between adjacent forward ratios and betweenthe reverse and first forward ratio.

The powertrain 910, shown in FIG. 10 a, includes the conventional engine12, a planetary transmission 914, and the conventional final drivemechanism 16. The engine 12 is drivingly connected with the planetarytransmission 914 through the input shaft 17. The planetary transmission914 is drivingly connected with the final drive mechanism 16 through theoutput shaft 19. The planetary transmission 914 includes a planetarygear arrangement 918 that has a first planetary gear set 920, a secondplanetary gear set 930, and a third planetary gear set 940.

The planetary gear set 920 includes a sun gear member 922, a ring gearmember 924, and a planet carrier assembly 926. The planet carrierassembly 926 includes a plurality of pinion gears 927 that are rotatablymounted on a carrier member 929 and disposed in meshing relationshipwith the sun gear member 922 and the ring gear member 924, respectively.

The planetary gear set 930 includes a sun gear member 932, a ring gearmember 934, and a planet carrier assembly member 936. The planet carrierassembly member 936 includes a plurality of pinion gears 937 rotatablymounted on a carrier member 939 and disposed in meshing relationshipwith both the ring gear member 934 and the sun gear member 932.

The planetary gear set 940 includes a sun gear member 942, a ring gearmember 944, and a planet carrier assembly member 946. The planet carrierassembly member 946 includes a plurality of pinion gears 947 rotatablymounted on a carrier member 949 and disposed in meshing relationshipwith both the sun gear member 942 and the ring gear member 944.

The planetary gear arrangement 918 also includes seventorque-transmitting mechanisms 950, 952, 954, 956, 957, 958 and 959. Thetorque-transmitting mechanisms 950, 952, 954, 956, 957 and 958 arerotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanism 959 is a stationary-typetorque-transmitting mechanism, commonly termed brake or reaction clutch.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 944. The planet carrier assembly member 926 is continuouslyconnected with the ring gear member 934 through the interconnectingmember 970. The planet carrier assembly member 936 is continuouslyconnected with the planet carrier assembly member 946 through theinterconnecting member 972. The sun gear member 932 is continuouslyconnected with the transmission housing 960.

The planet carrier assembly member 926 is selectively connectable withthe input shaft 17 through the clutch 950. The sun gear member 922 isselectively connectable with the input shaft 17 through the clutch 952.The planet carrier assembly member 936 is selectively connectable withthe input shaft 17 through the clutch 954. The planet carrier assemblymember 926 is selectively connectable with the ring gear member 944through the clutch 956. The ring gear member 924 is selectivelyconnectable with the ring gear member 944 through the clutch 957. Thering gear member 924 is selectively connectable with the sun gear member942 through the clutch 958. The planet carrier assembly member 936 isselectively connectable with the transmission housing 960 through thebrake 959.

The truth table of FIG. 10 b describes the torque-transmitting mechanismengagement sequence utilized to provide one reverse speed ratio andeight forward speed ratios, as well as an extra fifth forward speedratio. The truth table also provides a set of examples for the ratiosfor each of the reverse and forward speed ratios. These numerical valueshave been determined utilizing the ring gear/sun gear tooth ratios givenin FIG. 10 b. The N_(R1)/N_(S1) value is the tooth ratio of theplanetary gear set 920; the N_(R2)/N_(S2) value is the tooth ratio ofthe planetary gear set 930; and the N_(R3)/N_(S3) value is the toothratio of the planetary gear set 940.

A powertrain 1010, shown in FIG. 11 a, includes the conventional engine12, a planetary transmission 1014, and the conventional final drivemechanism 16. The engine is drivingly connected with the planetarytransmission 1014 through the input shaft 17. The planetary transmission1014 is drivingly connected with the final drive mechanism 16 throughthe output shaft 19. The planetary transmission 1014 includes aplanetary gear arrangement 1018 that has a first planetary gear set1020, a second planetary gear set 1030, and a third planetary gear set1040.

The planetary gear set 1020 includes a sun gear member 1022, a ring gearmember 1024, and a planet carrier assembly 1026. The planet carrierassembly 1026 includes a plurality of pinion gears 1027 rotatablymounted on a carrier member 1029 and disposed in meshing relationshipwith both the sun gear member 1022 and the ring gear member 1024.

The planetary gear set 1030 includes a sun gear member 1032, a ring gearmember 1034, and a planet carrier assembly member 1036. The planetcarrier assembly member 1036 includes a plurality of pinion gears 1037rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with both the ring gear member 1034 and the sun gear member1032.

The planetary gear set 1040 includes a sun gear member 1042, a ring gearmember 1044, and a planet carrier assembly member 1046. The planetcarrier assembly member 1046 includes a plurality of pinion gears 1047rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with both the ring gear member 1044 and the sun gear member1042.

The planetary gear arrangement 1018 also includes seventorque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057, 1058 and1059. The torque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057and 1058 are rotating-type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1059 is astationary-type torque-transmitting mechanism, commonly termed brake orreaction clutch.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 1026. The ring gear member 1024 is continuouslyconnected with the planet carrier assembly member 1036 through theinterconnecting member 1070. The ring gear member 1034 is continuouslyconnected with the planet carrier assembly member 1046 through theinterconnecting member 1072. The sun gear member 1032 is continuouslyconnected with the transmission housing 1060.

The planet carrier assembly member 1036 is selectively connectable withthe input shaft 17 through the clutch 1050. The ring gear member 1044 isselectively connectable with the input shaft 17 through the clutch 1052.The planet carrier assembly member 1026 is selectively connectable withthe ring gear member 1034 through the clutch 1054. The planet carrierassembly member 1026 is selectively connectable with the ring gearmember 1044 through the clutch 1056. The sun gear member 1022 isselectively connectable with the ring gear member 1044 through theclutch 1057. The sun gear member 1022 is selectively connectable withthe sun gear member 1042 through the clutch 1058. The ring gear member1024 is selectively connectable with the transmission housing 1060through the brake 1059.

The truth table shown in FIG. 11 b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand eight forward speed ratios, as well as the extra seventh speedratio. A sample of the numerical values for the ratios is also providedin the truth table of FIG. 11 b. These values are determined utilizingthe ring gear/sun gear tooth ratios also given in FIG. 11 b. TheN_(R1)/N_(S1) value is the tooth ratio for the planetary gear set 1020;the N₂/N_(S2) value is the tooth ratio for the planetary gear set 1030;and the N_(R3)/N_(S3) value is the tooth ratio for the planetary gearset 1040. Also given in FIG. 11 b is a chart describing the step ratiosbetween the adjacent forward speed ratios and the reverse to firstforward speed ratio.

A powertrain 1110, shown in FIG. 12 a, includes the conventional engine12, a planetary transmission 1114, and the conventional final drivemechanism 16. The engine is drivingly connected with the planetarytransmission 1114 through the input shaft 17. The planetary transmission1114 is drivingly connected with the final drive mechanism 16 throughthe output shaft 19. The planetary transmission 1114 includes aplanetary gear arrangement 1118 that has a first planetary gear set1120, a second planetary gear set 1130, and a third planetary gear set1140.

The planetary gear set 1120 includes a sun gear member 1122, a ring gearmember 1124, and a planet carrier assembly member 1126. The planetcarrier assembly member 1126 includes a plurality of pinion gears 1127rotatably mounted on a carrier member 1129 and disposed in meshingrelationship with both the sun gear member 1122 and the ring gear member1124.

The planetary gear set 1130 includes a sun gear member 1132, a ring gearmember 1134, and a planet carrier assembly member 1136. The planetcarrier assembly member 1136 includes a plurality of pinion gears 1137rotatably mounted on a carrier member 1139 and disposed in meshingrelationship with both the sun gear member 1132 and the ring gear member1134.

The planetary gear set 1140 includes a sun gear member 142, a ring gearmember 1144, and a planet carrier assembly member 1146. The planetcarrier assembly member 1146 includes a plurality of pinion gears 1147rotatably mounted on a carrier member 1149 and disposed in meshingrelationship with the ring gear member 1144 and the sun gear member1142.

The planetary gear arrangement 1118 also includes seventorque-transmitting mechanisms 1150, 1152, 1154, 1156, 1157, 1158 and1159. The torque-transmitting mechanisms 1150, 1152, 1154, 1156, 1157and 1158 are rotating type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1159 is astationary-type torque-transmitting mechanism, commonly termed brake orreaction clutch.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 1146. The sun gear member 1122 is continuouslyconnected with the ring gear member 1134 through the interconnectingmember 1170. The sun gear member 1132 is continuously connected with thering gear member 1144 through the interconnecting member 1172. Theplanet carrier assembly member 1136 is continuously connected with thetransmission housing 1160.

The planet carrier assembly member 1126 is selectively connectable withthe input shaft 17 through the clutch 1150. The sun gear member 1142 isselectively connectable with the input shaft 17 through the clutch 1152.The ring gear member 1124 is selectively connectable with the planetcarrier assembly member 1126 through the clutch 1154. The planet carrierassembly member 1126 is selectively connectable with the sun gear member1132 through the clutch 1156. The ring gear member 1124 is selectivelyconnectable with the sun gear member 1142 through the clutch 1157. Thering gear member 1124 is selectively connectable with the planet carrierassembly member 1146 through the clutch 1158. The planet carrierassembly member 1126 is selectively connectable with the transmissionhousing 1160 through the brake 1159.

The truth table shown in FIG. 12 b describes the engagement combinationsand the engagement sequence necessary to provide two reverse driveratios and eight forward speed ratios. A sample of the numerical valuesfor the ratios is also provided in the truth table of FIG. 12 b. Thevalues are determined utilizing the ring gear/sun gear tooth ratios alsogiven in FIG. 12 b. The N_(R1)/S_(R1) value is the tooth ratio of theplanetary gear set 1120; the N_(R2)/S_(R2) value is the tooth ratio ofthe planetary gear set 1130; and the N_(R3)/S_(R3) value is the toothratio of the planetary gear set 1140. Also given in FIG. 12 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reverse to first forward speed ratio. For example, step ratiobetween the first and second forward speed ratios is 2.38.

A powertrain 1210, shown in FIG. 13 a, includes the conventional engine12, a planetary transmission 1214, and the conventional final drivemechanism 16. The engine is drivingly connected with the planetarytransmission 1214 through the input shaft 17. The planetary transmission1214 is drivingly connected with the final drive mechanism 16 throughthe output shaft 19. The planetary transmission 1214 includes aplanetary gear arrangement 1218 that has a first planetary gear set1220, a second planetary gear set 1230, and a third planetary gear set1240.

The planetary gear set 1220 includes a sun gear member 1222, a ring gearmember 1224, and a planet carrier assembly member 1226. The planetcarrier assembly member 1226 includes a plurality of pinion gears 1227rotatably mounted on a carrier member 1229 and disposed in meshingrelationship with both the ring gear member 1224 and the sun gear member1222.

The planetary gear set 1230 includes a sun gear member 1232, a ring gearmember 1234, and a planet carrier assembly member 1236. The planetcarrier assembly member 1236 includes a plurality of pinion gears 1237rotatably mounted on a carrier member 1239 and disposed in meshingrelationship with the ring gear member 1234 and the sun gear member1232.

The planetary gear set 1240 includes a sun gear member 1242, a ring gearmember 1244, and a planet carrier assembly member 1246. The planetcarrier assembly member 1246 includes a plurality of pinion gears 1247rotatably mounted on a carrier member 1249 and disposed in meshingrelationship with both the sun gear member 1242 and the ring gear member1244.

The planetary gear arrangement 1218 also includes seventorque-transmitting mechanisms 1250, 1252, 1254, 1256, 1257, 1258 and1259. The torque-transmitting mechanisms 1250, 1252, 1254, 1256, 1257and 1258 are rotating type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1259 is a stationarytype torque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 1224. The sun gear member 1222 is continuously connected with thesun gear member 1232 through the interconnecting member 1270. The planetcarrier assembly member 1236 is continuously connected with the sun gearmember 1242 through the interconnecting member 1272. The ring gearmember 1234 is continuously connected with the transmission housing1260.

The planet carrier assembly member 1226 is selectively connectable withthe input shaft 17 through the clutch 1250. The planet carrier assemblymember 1246 is selectively connectable with the input shaft 17 throughthe clutch 1252. The ring gear member 1244 is selectively connectablewith the input shaft 17 through the clutch 1254. The sun gear member1232 is selectively connectable with the planet carrier assembly member1246 through the clutch 1256. The sun gear member 1232 is selectivelyconnectable with the ring gear member 1244 through the clutch 1257. Thering gear member 1224 is selectively connectable with the planet carrierassembly member 1236 through the clutch 1258. The planet carrierassembly member 1236 is selectively connectable with the transmissionhousing 1260 through the brake 1259.

The truth table shown in FIG. 13 b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand eight forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 13 b. These valuesare determined utilizing the ring gear/sun gear tooth ratios also givenin FIG. 13 b. The N_(R1)/S_(R1) value is the tooth ratio of theplanetary gear set 1220; the N_(R2)/S_(R2) value is the tooth ratio ofthe planetary gear set 1230; and the N_(R3)/S_(R3) value is the toothratio of the planetary gear set 1240. Also given in FIG. 13 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reverse to first forward speed ratio.

A powertrain 1310, shown in FIG. 14 a, includes the conventional engineand torque converter 12, a planetary transmission 1314, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1314 through theinput shaft 17. The planetary transmission 1314 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1314 includes a planetary gear arrangement 1318that has a first planetary gear set 1320, a second planetary gear set1330, and a third planetary gear set 1340.

The planetary gear set 1320 includes a sun gear member 1322, a ring gearmember 1324, and a planet carrier assembly 1326. The planet carrierassembly 1326 includes a plurality of pinion gears 1327 rotatablymounted on a carrier member 1329 and disposed in meshing relationshipwith both the sun gear member 1322 and the ring gear member 1324.

The planetary gear set 1330 includes a sun gear member 1332, a ring gearmember 1334, and a planet carrier assembly member 1336. The planetcarrier assembly member 1336 includes a plurality of pinion gears 1337rotatably mounted on a carrier member 1339 and disposed in meshingrelationship with the ring gear member 1334 and the sun gear member1332, respectively.

The planetary gear set 1340 includes a sun gear member 1342, a ring gearmember 1344, and a planet carrier assembly member 1346. The planetcarrier assembly member 1346 includes a plurality of pinion gears 1347rotatably mounted on a carrier member 1349 and disposed in meshingrelationship with both the sun gear member 1342 and the ring gear member1344.

The planetary gear arrangement 1318 also includes seventorque-transmitting mechanisms 1350, 1352, 1354, 1356, 1357, 1358 and1359. The torque-transmitting mechanisms 1350, 1352, 1354, 1356, 1357,1358 and 1359 are all rotating-type torque-transmitting mechanisms,commonly termed clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the sun gearmember 1322. The planet carrier assembly member 1326 is continuouslyconnected with the planet carrier assembly member 1336 through theinterconnecting member 1370. The ring gear member 1334 is continuouslyconnected with the ring gear member 1344 through the interconnectingmember 1372. The sun gear member 1332 is continuously connected with thetransmission housing 1360.

The planet carrier assembly member 1336 is selectively connectable withthe input shaft 17 through the clutch 1350. The planet carrier assemblymember 1346 is selectively connectable with the input shaft 17 throughthe clutch 1352. The planet carrier assembly member 1326 is selectivelyconnectable with the sun gear member 1342 through the clutch 1354. Thering gear member 1324 is selectively connectable with the sun gearmember 1342 through the clutch 1356. The ring gear member 1324 isselectively connectable with the planet carrier assembly member 1346through the clutch 1357. The sun gear member 1322 is selectivelyconnectable with the sun gear member 1342 through the clutch 1358. Thesun gear member 1322 is selectively connectable with the planet carrierassembly member 1346 through the clutch 1359.

The truth table shown in FIG. 14 b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand the eight forward speed ratios, as well as extra second, third,fourth and eighth forward speed ratios. A sample of the numerical valuesfor the ratios is also provided in the truth table of FIG. 14 b. Thesevalues are determined utilizing the ring gear/sun gear tooth ratios alsogiven in FIG. 14 b. The N_(R1)/N_(S1) value is the tooth ratio for theplanetary gear set 1320; the N_(R2)/N_(S2) value is the tooth ratio forthe planetary gear set 1330; and the N_(R3)/N_(S3) value is the toothratio for the planetary gear set 1340. Also given in FIG. 14 b is achart describing the step ratios between the adjacent forward speedratios and the reverse to first forward speed ratio.

A powertrain 1410, shown in FIG. 15 a, includes the conventional engineand torque converter 12, a planetary transmission 1414, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1414 through theinput shaft 17. The planetary transmission 1414 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1414 includes a planetary gear arrangement 1418that has a first planetary gear set 1420, a second planetary gear set1430, and a third planetary gear set 1440.

The planetary gear set 1420 includes a sun gear member 1422, a ring gearmember 1424, and a planet carrier assembly 1426. The planet carrierassembly 1426 includes a plurality of pinion gears 1427 rotatablymounted on a carrier member 1429 and disposed in meshing relationshipwith both the sun gear member 1422 and the ring gear member 1424.

The planetary gear set 1430 includes a sun gear member 1432, a ring gearmember 1434, and a planet carrier assembly member 1436. The planetcarrier assembly member 1436 includes a plurality of pinion gears 1437rotatably mounted on a carrier member 1439 and disposed in meshingrelationship with both the sun gear member 1432 and the ring gear member1434.

The planetary gear set 1440 includes a sun gear member 1442, a ring gearmember 1444, and a planet carrier assembly member 1446. The planetcarrier assembly member 1446 includes a plurality of pinion gears 1447,1448 rotatably mounted on a carrier member 1449 and disposed in meshingrelationship with the sun gear member 1442 and the ring gear member1444, respectively.

The planetary gear arrangement 1418 also includes seventorque-transmitting mechanisms 1450, 1452, 1454, 1456, 1457, 1458 and1459. The torque-transmitting mechanisms 1450, 1452, 1454, 1456, 1457and 1458 are rotating-type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1459 is a stationarytype torque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the sun gearmember 1442. The planet carrier assembly member 1426 is continuouslyconnected with the ring gear member 1434 through the interconnectingmember 1470. The planet carrier assembly member 1436 is continuouslyconnected with the ring gear member 1444 through the interconnectingmember 1472. The sun gear member 1432 is continuously connected with thetransmission housing 1460.

The planet carrier assembly member 1426 is selectively connectable withthe input shaft 17 through the clutch 1450. The sun gear member 1422 isselectively connectable with the input shaft 17 through the clutch 1452.The ring gear member 1424 is selectively connectable with the inputshaft 17 through the clutch 1454. The sun gear member 1422 isselectively connectable with the planet carrier assembly member 1436through the clutch 1456. The ring gear member 1424 is selectivelyconnectable with the planet carrier assembly member 1446 through theclutch 1457. The ring gear member 1424 is selectively connectable withthe sun gear member 1442 through the clutch 1458. The planet carrierassembly member 1436 is selectively connectable with the transmissionhousing 1460 through the brake 1459.

The truth table shown in FIG. 15 b describes the engagement combinationsand the engagement sequence necessary to provide two reverse drive ratioand the nine forward speed ratios, as well as an extra fifth forwardspeed ratio. A sample of the numerical values for the ratios is alsoprovided in the truth table of FIG. 15 b. These values are determinedutilizing the ring gear/sun gear tooth ratios also given in FIG. 15 b.The N_(R1)/N_(S1) value is the tooth ratio for the planetary gear set1420; the N_(R2)/N_(S2) value is the tooth ratio for the planetary gearset 1430; and the N_(R3)/N_(S3) value is the tooth ratio for theplanetary gear set 1440. Also given in FIG. 15 b is a chart describingthe step ratios between the adjacent forward speed ratios and thereverse to first forward speed ratio.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input shaft; an outputshaft; first, second and third planetary gear sets each having first,second and third members; said output shaft being continuouslyinterconnected with a member of said planetary gear sets, and said inputshaft not being continuously interconnected with any member of saidplanetary gear sets; a first interconnecting member continuouslyinterconnecting said first member of said first planetary gear set withsaid first member of said second planetary gear set; a secondinterconnecting member continuously interconnecting said second memberof said second planetary gear set with said first member of said thirdplanetary gear set; said third member of said second planetary gear setbeing continuously interconnected with a stationary member; a firsttorque-transmitting mechanism selectively interconnecting a member ofsaid first or third planetary gear set with said input shaft; a secondtorque-transmitting mechanism selectively interconnecting another memberof said first or third planetary gear set with said input shaft; a thirdtorque-transmitting mechanism selectively interconnecting a member ofsaid first, second or third planetary gear set with said input shaft orwith another member of said first, second or third planetary gear set; afourth torque-transmitting mechanism selectively interconnecting amember of said first planetary gear set with a member of said second orthird planetary gear set; a fifth torque-transmitting mechanismselectively interconnecting a member of said first or third planetarygear set with another member of said first or third planetary gear set,or with said stationary member; a sixth torque-transmitting mechanismselectively interconnecting a member of said first or third planetarygear set with another member of said first, second or third planetarygear set, or with said stationary member; and a seventhtorque-transmitting mechanism selectively interconnecting a member ofsaid first, second or third planetary gear set with another member ofsaid first, second or third planetary gear set, or with said stationarymember; said torque-transmitting mechanisms being engaged incombinations of three to establish at least eight forward speed ratiosand at least one reverse speed ratio between said input shaft and saidoutput shaft.
 2. The transmission defined in claim 1, wherein saidfirst, second, third, fourth, fifth, sixth and seventhtorque-transmitting mechanisms comprise clutches.
 3. The transmissiondefined in claim 1, wherein said first, second, third and fourthtorque-transmitting mechanisms comprise clutches, and said fifth, sixthand seventh torque-transmitting mechanisms comprise brakes.
 4. Thetransmission defined in claim 1, wherein said first, second, third,fourth and fifth torque-transmitting mechanisms comprise clutches, andsaid sixth and seventh torque-transmitting mechanisms comprise brakes.5. The transmission defined in claim 1, wherein said first, second,third, fourth, fifth and sixth torque-transmitting mechanisms compriseclutches, and said seventh torque-transmitting mechanism comprises abrake.
 6. The transmission defined in claim 1, wherein said first,second, third, fourth, fifth and seventh torque-transmitting mechanismscomprise clutches, and said sixth torque-transmitting mechanismcomprises a brake.
 7. The transmission defined in claim 1, wherein saidfirst, second, third, fourth and sixth torque-transmitting mechanismscomprise clutches, and said fifth and seventh torque-transmittingmechanisms comprise brakes.
 8. The transmission defined in claim 1,wherein planet carrier assembly members of each of said planetary gearsets are single-pinion carriers.
 9. The transmission defined in claim 1,wherein at least one planet carrier assembly member of said planetarygear sets is a double-pinion carrier.
 10. A multi-speed transmissioncomprising: an input shaft; an output shaft; a planetary geararrangement having first, second and third planetary gear sets, eachplanetary gear set having first, second and third members; said outputshaft being continuously interconnected with a member of said planetarygear sets, and said input shaft not being continuously interconnectedwith any member of said planetary gear sets; a first interconnectingmember continuously interconnecting said first member of said firstplanetary gear set with said first member of said second planetary gearset; a second interconnecting member continuously interconnecting saidsecond member of said second planetary gear set with said first memberof said third planetary gear set; said third member of said secondplanetary gear set being continuously interconnected with a stationarymember; and seven torque-transmitting mechanisms for selectivelyinterconnecting said members of said planetary gear sets with said inputshaft, with said stationary member or with other members of saidplanetary gear sets, said seven torque-transmitting mechanisms beingengaged in combinations of three to establish at least eight forwardspeed ratios and at least one reverse speed ratio between said inputshaft and said output shaft.
 11. The transmission defined in claim 10,wherein a first of said seven torque-transmitting mechanisms is operablefor selectively interconnecting a member of said first or thirdplanetary gear set with said input shaft.
 12. The transmission definedin claim 10, wherein a second of said seven torque-transmittingmechanisms is operable for selectively interconnecting a member of saidfirst or third planetary gear set with said input shaft.
 13. Thetransmission defined in claim 10, wherein a third of said seventorque-transmitting mechanisms is selectively operable forinterconnecting a member of said first, second or third planetary gearset with said input shaft or with another member of said first, secondor third planetary gear set.
 14. The transmission defined in claim 10,wherein a fourth of said seven torque-transmitting mechanisms isselectively operable for interconnecting a member of said firstplanetary gear set with a member of said second or third planetary gearset.
 15. The transmission defined in claim 10, wherein a fifth of saidseven torque-transmitting mechanisms is selectively operable forinterconnecting a member of said first or third planetary gear set withanother member of said first or third planetary gear set, or with saidstationary member.
 16. The transmission defined in claim 10, wherein asixth of said seven torque-transmitting mechanisms selectivelyinterconnects a member of said first or third planetary gear set withanother member of said first, second or third planetary gear set, orwith said stationary member.
 17. The transmission defined in claim 10,wherein a seventh of said seven torque-transmitting mechanismsselectively interconnects a member of said first, second or thirdplanetary gear set with another member of said first, second or thirdplanetary gear set, or with said stationary member.
 18. The transmissiondefined in claim 10, wherein planet carrier assembly members of each ofsaid planetary gear sets are single-pinion carriers.
 19. Thetransmission defined in claim 10, wherein at least one planet carrierassembly member of said planetary gear sets is a double-pinion carrier.